The present invention relates to toothbrushes, in particular to mechanically-driven toothbrushes, such as, e.g., electric toothbrushes powered by rechargeable batteries that power an electric motor that in turn drives the toothbrush head.
There exist a great variety of tooth-brushing techniques as well as of toothbrushes of both manual and mechanically-driven types. In general, almost all known techniques recommend to brush the outer surfaces of the teeth in the sidewise direction, i.e., in the transverse direction of the teeth. Such cleaning technique does not provide efficient removal of plaque from between the teeth since the bristles will simply slide over the spaces between the adjacent teeth and will not penetrate deep into these spaces. Brushing in a vertical direction of the teeth is recommended only for the inner surfaces of the front teeth.
Almost all existing electrically-driven toothbrushes are designed based on the above concept of sidewise brushing. In terms of movements of the toothbrush head, the existing electric toothbrushes can be divided into brushes with rotary or spinning movement of the brush head and linearly-reciprocating brushy heads. U.S. Pat. No. 5,974,615 issued in 1999 to A. Schwartz-Hartmann, et al. discloses an electric toothbrush, which incorporates a handle and a brush attachment. The handle houses an electric motor. Through a conversion gear and cranking mechanism, rotation of the shaft of the motor is converted into alternating rotations of the shaft, which are transmitted via an intermediate shaft of the brush attachment, connectable to the drive, to the brush head. Through a special cam mechanism the intermediate shaft, and hence, the brush head, also performs stroke motion in the direction transverse to the longitudinal direction of the shaft. The frequency of the stroke movement is higher than the frequency of the rotary movement. In operation, the brush head is oriented with the bristle ends facing the surfaces of the teeth. The stroke movement serves for a poking action of the bristles, which serves to loosen plaque from dental surfaces. The rotary movement serves to wipe away plaque loosened from the dental surfaces. However, because of the rotation of the brush head, the poking motion of the brush is not very efficient. The poking effect of the poking motion is also insufficient since the poking motions are linear in the direction perpendicular to the surfaces of the teeth. In addition, the toothbrush of this type has the same disadvantages as those inherent in electric toothbrushes with the angular transmission, i.e., more complicated structure and shorter service life.
U.S. Pat. No. 5,613,258 issued in 1997 to P. Hilfinger et al. discloses an electric toothbrush with an angularly-driven brush head having a conically-shaped brush intended specifically for removing plaque accumulated between the teeth. Along with disadvantages of the angular transmission, this toothbrush is intended for a specific operation and requires the use of a second general-purpose toothbrush.
It is an object of the invention to provide a mechanically-driven toothbrush without an angular transmission and with direct connection of the brush head to a driving shaft that performs alternating angular rotations transmitted to the coaxial brush head. Another object of the invention is to provide a toothbrush attachment connectable to a standard mechanically-driven toothbrush handle that incorporates a drive motor with the shaft projecting from the handle and performing alternating angular rotations. Still another object is to provide a mechanically-driven toothbrush with a brush head that imitates movements of a toothpick for efficient removal of plaque from the spaced between the teeth. Another object is to provide a mechanically-driven toothbrush with a brush head intended for brushing in an up-and-down direction over the tooth surface.